The modern craft beer scene is rich with big, extreme beers — beers with higher alcohol levels, more hops, more malt and more everything. The surge stems in part from brewers who are constantly pushing the envelope, making stronger, more complex and bigger beers, but there’s also a passionate fan base for these styles. Big beers may not appeal to everyone, but those who love them are passionate about it.

One of the most popular of these extreme beers stems from a style that dates back at least to the 18th century.

Russian imperial stout

Imperial stouts, with or without the Russian appellation, are some of the strongest beers in the beer-style panoply, with an alcohol by volume content, or a.b.v., between 8 and 12 percent. Some of today’s American interpretations run even higher.

To understand the popularity of this strong imperial stout, travel back in time to 1822. Beer drinkers in Russia and the Baltic states liked any strong beer, and English brewers had been supplying them with a variety of different brews. But in 1822, the Russian government imposed a tariff that effectively banned a wide range of British products, including “Shrub, Liquors, Ale and Cyder.” Dark beers — what we now call porter and stout — were not specifically included, creating a loophole that allowed those styles to keep flowing.

Legend has it that Russia’s czars, including Catherine the Great in the 18th century, were fans of this beer, so the “imperial” nickname may be warranted. But the beer wasn’t dubbed Russian imperial stout until the early 20th century.

The Mad Monk

You don’t have to go as far as Russia or even England to find an imperial stout. One of the best Russian imperial stouts brewed anywhere is made in Fort Bragg. North Coast Brewing’s Old Rasputin Russian Imperial Stout was one of the first brewed on these shores and one of the oldest still being made. I visited the Fort Bragg brewery last week to talk with founder Mark Ruedrich and watch the latest batch of Old Rasputin being bottled.

When it opened in 1988, North Coast had a terrific stout called Old No. 38. But when Ruedrich decided he wanted to do something different, he realized that nearly anyone was making an imperial style anymore, not even in England. So he set to work to brew an authentic version of the style.

Shortly before its 1994 debut at the pub, Tom Dalldorf, publisher of the Celebrator Beer News, happened to be in town. He recalls Ruedrich handing him a glass and explaining that it was a new beer he planned to release. Dalldorf saw its inky black color and asked, “Don’t you already make a stout?” This one was different, Ruedrich told him. It was.

The beer boasts gorgeous milk chocolate and roasted coffee notes and warming sweet flavors from its 9 percent a.b.v. It’s as bold as they come and infinitely complex, an everlasting gobstopper of a beer. It also enjoys near-perfect balance. It’s a sipping beer, and it changes as it warms in your glass. It’s a not a beer for a pint glass; you’ll want a snifter to get the full aromas as you slowly sip it by the fire.

Take a peek at the label, too. It includes a traditional Russian proverb that translates to “A sincere friend is not born instantly.” If you’re a fan of big beers, your love for this beer almost certainly will be instantaneous.

More imperialists

You can’t go wrong with Old Rasputin — or its even bigger brother, Old Rasputin XIV, which is aged in bourbon barrels — but there are other imperial stouts available in the Bay Area, too. Among those worth pouring in your snifter: Firestone Walker’s Parabola, Stone Brewing’s Imperial Russian Stout, and Oskar Blues’ Ten FIDY, which is available in a can. Also terrific: Lagunitas Imperial Stout, Moylan’s Ryan O’Sullivan’s, Drake’s Drakonic, Eel River’s Raven’s Eye and FiftyFifty’s Totality Imperial Stout. FiftyFifty also makes Eclipse, which is Totality aged in bourbon barrels.